Conventional integrated circuits include a clock input pin for receiving a clock signal from an integrated circuit timing device or include an input pin that connects to a piezoelectric crystal and an output pin that provides a feedback clock signal to the piezoelectric crystal. In order to meet the needs of these two types of integrated circuits a wide range of integrated circuit timing devices have been developed.
In many cases a system may start with an integrated circuit that connects to a piezoelectric crystal and then subsequent products may move up to a more sophisticated integrated circuit that requires a more complex and more accurate integrated circuit timing device. In these instances, the system manufacturer must first design a system that includes a piezoelectric crystal and implement connections to the piezoelectric crystal and then later redesign the system to accommodate a conventional integrated circuit timing device.
This adds expense to the product upgrade process that would be unnecessary if a single integrated circuit timing device could be used both as a replacement for a piezoelectric crystal and as a conventional integrated circuit timing device. Accordingly, there is a need for a single integrated circuit timing device that can be used both as a replacement for a piezoelectric crystal and as a conventional integrated circuit timing device.